Valve for single-use applications

ABSTRACT

A centerbody assembly for a valve includes: a centerbody having a first side which defines a process surface and an opposed second side defining a back surface, at least one inlet orifice disposed in the centerbody and adapted to be disposed in fluid communication with a fluid at a process pressure, and at least one outlet orifice disposed in the centerbody separate from the at least one inlet orifice; an inlet port disposed in fluid communication with the at least one inlet orifice; an outlet port disposed in fluid communication with the at least one outlet orifice; and a flexible control diaphragm having opposed reference and process sides, wherein the control diaphragm is positioned with the process side facing the process surface, and a perimeter of the control diaphragm is sealed to the centerbody.

BACKGROUND OF THE INVENTION

The present invention relates to valves, and more particularly to valveswhich are suitable for single-use applications.

Chemical and biological manufacturing processes typically requirecomplex piping systems to route fluids between and among equipment suchas storage vessels, reactors, distillation columns, and the like. Thesepiping systems typically include multiple conduits, couplingsregulators, and valves.

In such processes, there is a need for fluid control valves and on/offvalves to control process pressure over wide pressure ranges, such asfrom 0.1 bar to 10 bar, while also controlling across wide flow ranges(wider than traditional control valves, which are approximately 20:1)such as 50:1 or 100:1 flow range ratios. There is also a need forsensitive flow control valves that work well with computer automationand function across wide flow rate ranges (greater than traditionalcontrol valves).

Furthermore, in certain industries, especially bio-pharmaceuticalmanufacturing, there is a desire to reduce overhead costs associatedwith cleaning and validation of a sterile work environment.

One problem with existing pressure regulators and similar valves is thatthey must be capable of maintaining sterile conditions while alsoresisting operating pressures. This drives them to be manufactured fromheavy, expensive materials such as stainless steel which can besterilized or re-sterilized (e.g., through autoclave processes). Thisneed must also balance against the requirement to provide pressurecontrol with high accuracy in certain biopharma processes, such as mediafiltration.

BRIEF SUMMARY OF THE INVENTION

This problem is addressed by a valve of the type using a direct-sealingdiaphragm. Described herein are several embodiments of this type ofvalve which are especially suitable for single-use or disposal afteruse, incorporating one or more features to maintain sterility andminimize waste.

According to one aspect of the technology described herein, a centerbodyassembly for a valve includes: a centerbody having a first side whichdefines a process surface and an opposed second side defining a backsurface, at least one inlet orifice disposed in the centerbody andadapted to be disposed in fluid communication with a fluid at a processpressure, and at least one outlet orifice disposed in the centerbodyseparate from the at least one inlet orifice; an inlet port disposed influid communication with the at least one inlet orifice; an outlet portdisposed in fluid communication with the at least one outlet orifice;and a flexible control diaphragm having opposed reference and processsides, wherein the control diaphragm is positioned with the process sidefacing the process surface, and a perimeter of the control diaphragm issealed to the centerbody.

According to another aspect of the technology described herein, a valveincludes: a centerbody assembly including: a centerbody having a firstside which defines a process surface and an opposed second side defininga back surface, at least one inlet orifice disposed in the centerbodyand adapted to be disposed in fluid communication with a fluid at aprocess pressure, and at least one outlet orifice disposed in thecenterbody separate from the at least one inlet orifice; a flexiblecontrol diaphragm having opposed reference and process sides, whereinthe control diaphragm is positioned with the process side facing theprocess surface, and a perimeter of the control diaphragm is sealed tothe centerbody; an inlet port disposed in fluid communication with theat least one inlet orifice; and an outlet port disposed in fluidcommunication with the at least one outlet orifice; and an enclosureassembly including a top cap adapted to be disposed in fluidcommunication with a fluid at a predetermined reference pressure,wherein the control diaphragm is positioned between the centerbody andthe top cap, and arranged such that, when the reference pressure ishigher than the process pressure the diaphragm is engaged with theoutlet orifices, and when the process pressure is higher than thereference pressure, the diaphragm is not engaged with at least one ofthe outlet orifices.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be best understood by reference to the followingdescription taken in conjunction with the accompanying drawing figuresin which:

FIG. 1 is a top perspective view showing an exemplary embodiment of avalve;

FIG. 2 is a bottom perspective view of the valve shown in FIG. 1;

FIG. 3 is a front elevation view of the valve shown in FIG. 1;

FIG. 4 is a front elevation view of the valve shown in FIG. 1, with aclamp thereof removed;

FIG. 5 is a cross-sectional view of the valve as shown in FIG. 4;

FIG. 6 is a perspective view showing a centerbody of the valve of FIG.1;

FIG. 7 is a top plan view of the centerbody of FIG. 6;

FIG. 8 is a top perspective view of a centerbody assembly incorporatingthe centerbody shown in FIG. 7;

FIG. 9 is a bottom perspective view of the centerbody assembly shown inFIG. 8;

FIG. 10 is an exploded perspective view of the valve of FIG. 1;

FIG. 11 is a cross-sectional view of an alternative centerbody for useof the valve of FIG. 1;

FIG. 12 is a flow diagram of the valve of FIG. 1 connected to a fluidsystem;

FIG. 13 is an exploded perspective view of an alternative embodiment ofa valve;

FIG. 14 is a top perspective view of a centerbody of the valve of FIG.13;

FIG. 15 is a bottom perspective view of the centerbody of FIG. 14;

FIG. 16 is a top plan view of the centerbody of FIG. 14;

FIG. 17 is a sectional view taken along lines 17-17 of FIG. 16;

FIG. 18 is a perspective view of a centerbody assembly of the valve ofFIG. 13 incorporating the centerbody of FIG. 14;

FIG. 19 is an exploded view of the centerbody assembly of FIG. 18;

FIG. 20 is a cross-sectional view of the assembled valve of FIG. 14;

FIG. 21 is a schematic cross-sectional view of another embodiment of avalve;

FIG. 22 is a sectional view of a portion of a centerbody showing oneconfiguration of mechanical sealing of a diaphragm;

FIG. 23 is a sectional view of a portion of a centerbody showing analternative configuration of mechanical sealing of a diaphragm;

FIG. 24 is a sectional view of a portion of a centerbody showing analternative configuration of mechanical sealing of a diaphragm; and

FIG. 25 is a sectional view of a portion of a centerbody showing analternative configuration of mechanical sealing of a diaphragm.

DETAILED DESCRIPTION OF THE INVENTION

Now, referring to the drawings wherein identical reference numeralsdenote the same elements throughout the various views, FIGS. 1-5illustrate an exemplary valve 100 constructed according to one aspect ofthe present invention. It is noted that the basic construction describedherein can serve as a back pressure regulator or a flow control valve,though “valve” will be referenced in this document for both functions.

The basic components of the valve 100 are a centerbody assembly 102(FIG. 9) and an enclosure assembly 104 including a top cap (or referencecap) 106 and a bottom support 108.

The centerbody assembly 102 includes a centerbody 110 having a firstside defining a process surface 112, and an opposed second side defininga back surface 114. Both of the surfaces 112, 114 are generally planarin the illustrated example, but different geometries may be used, forexample, the surfaces 112, 114 may include various recesses orprotrusions.

At least one inlet orifice 116 passes through the centerbody 110 fromthe process surface 112 to the back surface 114. The function of theinlet orifice (or orifices) 116 is to bring the process fluid into thevalve 100. At least one outlet orifice 118 passes through the centerbody110 from the process surface 112 to the back surface 114. The functionof the outlet orifice (or orifices) 118 is to vent process fluid fromthe valve 100.

The centerbody 110 (containing the orifices) may be manufactured usingvarious methods such as machining from a block of precursor material,additive manufacturing processes (e.g., “3-D printing”), or molding froma polymer suitable for the application requirements. For bestperformance in a single-use application where sterility is important, apolymer with USP class VI certification may be used. Nonlimitingexamples of such materials include polyolefin (e.g., polyethylene, LDPE,HDPE, UHMWPE), PEEK, acetal polymer (e.g. DELRIN), PTFE, and PFA.

A flexible control diaphragm or membrane 120 is disposed adjacent theprocess surface 112. For best performance in a single-use applicationwhere sterility is important, the control diaphragm 120 may be made froma material with USP class VI certification. Nonlimiting examples of suchmaterials include TPU, TPE, polyolefin (LDPE, HDPE, UHMWPE, PP, etc.),PEEK, PTFE, PFA, FEP, a sulfone polymer such as RADEL, silicone, orother similar thermoplastic elastomer such as SANTOPRENE.

The control diaphragm 120 has opposed sides, referred to as referenceand process sides, with the process side facing the process surface 112.The perimeter of the control diaphragm 120 is sealed to the centerbody110. As used herein, the term “sealed” implies that a boundary ispresent that blocks the passage of fluid, with the understanding thatsuch boundary is not required to resist any specific magnitude ofpressure differential. Rather, the seal is for the purpose of ensuringthat the control diaphragm 120 is in the correct position and secured inrobust enough manner to stay in place and maintain sterility duringshipping assembly.

Some nonlimiting examples of methods of creating a suitable seal includebonding methods, such as thermal bonding, sonic bonding, or adhesivebonding. Other options for sealing the control diaphragm 120 to thecenterbody 110 include mechanical seals. Some examples of mechanicalseals are illustrated in FIGS. 22-24.

FIG. 22 shows a control diaphragm 120 placed over the process surface112 of the centerbody 110, with a portion of the control diaphragm 120draped over a peripheral wall 111 of the centerbody 110. A shallowconcave peripheral groove 113 is formed in the peripheral wall 111. Aresilient seal 115 such as the illustrated O-ring surrounds the controldiaphragm 120 and forces it into the peripheral groove 113.

FIG. 23 shows a control diaphragm 120 placed over the process surface112 of the centerbody 110, with a portion of the control diaphragm 120draped over a peripheral wall 111 of the centerbody 110. Adovetail-shaped peripheral groove 113 is formed in the peripheral wall111. A resilient seal 115 such as the illustrated O-ring surrounds thecontrol diaphragm 120 and forces it into the peripheral groove 113.

FIG. 24 shows a control diaphragm 120 placed over the process surface112 of the centerbody 110. A peripheral groove 113, such as a dovetailgroove, is formed in the process surface 112. A resilient seal 115 suchas the illustrated O-ring clamps the control diaphragm 120 into theperipheral groove 113.

FIG. 25 shows a control diaphragm 120 placed over the process surface ofthe centerbody 110. A retainer 115 clamps the control diaphragm 120against the peripheral wall 111 of the centerbody 110. Nonlimitingexamples of suitable retainers 115 include devices such as O-rings,elastic bands, “zip-ties”, hose clamps, and similar devices. Theseexemplary methods and configurations for sealing are applicable to anyof the diaphragm-to-centerbody connections described herein. The controldiaphragm 120 is continuous and is free from holes or other openingstherein, to form a fluid-tight boundary.

Referring back to FIGS. 1-5, in the illustrated example, the inletorifices 116 and outlet orifices 118 are formed as through-holes, whichmust be sealed off at the back surface 114 in order to define theappropriate fluid flowpath. Accordingly, a backside diaphragm ormembrane 122 is disposed adjacent the back surface 114. In one example,a thickness of the backside diaphragm 122 is less than 0.5 mm (0.02inches). In another example it may be less than 0.25 mm (0.01 inches).The backside diaphragm 122 could be made from any of the materialslisted for the control diaphragm 120. The perimeter of the backsidediaphragm 122 is sealed to the centerbody 110. The backside diaphragm122 includes an inlet opening 117 and an outlet opening 119.

In the illustrated example, separate inlet and outlet fittings 124, 126respectively, are provided. Each of these has a flange 128 which issecured to the backside diaphragm 122, for example by welding oradhesive, to serve as inlet and outlet ports 130, 132 respectively, ofthe valve 100. A fluid passage 134 of the inlet fitting 124 communicateswith the inlet opening 117 of the backside diaphragm 122, and a fluidpassage 137 of the outlet fitting 126 communicates with the outletopening 119 of the backside diaphragm 122. For best performance in asingle-use application where sterility is important, the inlet andoutlet fittings 124, 126 may be made of a USP class VI thermoplastic.Examples of such materials are described above.

As an alternative construction, the centerbody may be constructed (forexample using an additive manufacturing process) so as to include allnecessary fluid passages, including a collection cavity where two ormore outlet orifices are gathered together before exiting the valvethrough the outlet port. In a preferred embodiment, three or moreorifices are gathered together in this cavity. For example, FIG. 11illustrates a variation of a centerbody 110′ including a process surface112′, an opposed back surface 114′, a plurality of inlet orifices 116′,a plurality of outlet orifices 118′, an integral inlet fitting 124′, andan integral outlet fitting 126′. An inlet manifold 127 is formedintegrally with the centerbody 110 ‘and forms a fluid connection betweenthe inlet orifices 116’ and the inlet fitting 124′. An outlet manifold129 is formed integrally within the centerbody 110′ and forms a fluidconnection between the outlet orifices 118′ and the outlet fitting 126′.

Referring back to FIG. 5, the control diaphragm 120 may be contained byany support structure that is strong enough to provide physical supportfor the control diaphragm 120 up to the intended use pressure.Nonlimiting examples of potential maximum pressures include: up to 70kPa (10 psi), up to 400 kPa (60 psi), or up to 1000 kPa (150 psi). Thesupport structure may be constructed so as to be reusable. For example,it may be made of a metal or metal alloy such as stainless steel. Thesupport structure may be easily cleanable. In one example, the supportstructure has a surface finish of less than 32 RA (micro inch).

In the illustrated example, the enclosure assembly 104 includes top cap106 which serves as a support structure for the control diaphragm 120.The top 106 has a disk-like shape with an internal reference cavity 136and an integral reference port 138 connected in fluid communication withthe reference cavity 136. It also includes a beveled first annularflange 140 around its periphery. Depending on the union method betweendiaphragm 120 and regulator body 112, the top cap 106 may also need anadditional gasket 121 (FIG. 5) to appropriately apply additionalcompression to seal appropriately. This gasket 121 may be free-floatingor mechanically bonded to the top cap 106 via glue, compressioninterlocking, or other geometry.

In similar fashion, the backside diaphragm 122 may be supported byreusable support structure to provide greater pressure rating whileminimizing the quantity of single-use material. The configuration andmaterial of the support structure for the backside diaphragm 122 may besimilar to that of the support structure for the control diaphragm 120.

In the illustrated example, the enclosure assembly 104 includes bottomsupport 108 which serves as a support structure for the backsidediaphragm 122. The bottom support 108 has a disk-like shape withclearance openings 142 for the inlet and outlet fittings 126 describedabove. It also includes a beveled second annular flange 144 around itsperiphery.

Means are provided for joining the components of the enclosure assembly104 and to hold pressure forces. In the illustrated embodiment, seen inFIGS. 1-3 and FIG. 10, a ring-shaped clamp 146 incorporates a groove 148which engages and clamps together the first and second annular flanges140, 144. Another possible embodiment (not shown) would be a screwedretainer.

Optionally, the support structure may provide reinforcement to theperimeter seal of the control diaphragm 120 and/or the backsidediaphragm 122 by a crush seal configuration, allowing the centerbodyassembly 102 to be rated to higher pressure than could be withstood bythe single-use components alone. In the illustrated example, this crushseal is provided by clamping of selected portions of the centerbodyassembly 102 between the top cap 106 and the bottom support 108. Forexample, as seen in FIG. 5, the top cap 106 and the bottom support 108includes opposed rebates 150, 152 respectively, which receive aperimeter of the centerbody assembly 102 therebetween. As best seen inFIG. 10, the bottom support 108 further includes a rib 154 defining aclosed perimeter which defines another crush seal that isolates theinlet fitting 124 from the outlet fitting 126.

An example of this construction would be a thin diaphragm that may besuitable for use at maximum pressures in a range of 14 kPa (2 psi) to 70kPa (10 psi), considering normal safety factors of 3X to 5X relative tohydrostatic failure, without structure reinforcement. With the enclosureassembly 104 described above providing structural support of theperimeter bonds, the combination may be suitable for use up to 70 kPa(10 psi), up to 400 kPa (60 psi), or up to 1000 kPa (150 psi), or evenhigher pressures, again considering normal safety factors of 3X to 5Xrelative to hydrostatic failure.

FIG. 12 is a schematic representation of a representative industrialprocess incorporating the valve 100 described above. This is but one ofmany types of process system which utilize a control valve and/or backpressure regulator. The system includes a process vessel 200 coupled toa compressor 202 and a pressure gauge 204. The process vessel 200 isconnected to the inlet port 130 of the valve 100 by an inlet line 208.The reference port 138 of the valve 100 is connected to a pressurereference source 209 by a reference line 211. During normal balanced ormodulating mode, the control diaphragm 120 is drawn into a sealingrelationship with the outlet orifices 118 due to the pressuredifferential between the vessel pressure and reference pressure. Whenthe vessel pressure exceeds the reference pressure the area of thecontrol diaphragm 120 between the outlet orifices 118 is persuaded awayfrom the outlet orifices 118 thereby allowing venting through the outletport 132. In the illustrated example the outlet port 132 is coupled to acollection vessel 210. Optionally, the fluid may be discharged toatmosphere.

FIGS. 13-20 illustrate an alternative embodiment of a valve 300. Thevalve 300 is similar in overall construction to valve 100 describedabove and includes a centerbody assembly 302 and an enclosure assembly304 including a top cap (or reference cap) 306, a bottom support 308,and a retainer ring 309.

The centerbody assembly 302 (FIGS. 14-19) includes a centerbody 310having a first side defining a process surface 312, and an opposedsecond side defining a back surface 314. Both of the surfaces 312, 314are generally planar in the illustrated example, but differentgeometries may be used for example, the surfaces 312, 314 may includevarious recesses or protrusions.

A plurality of inlet orifices 316 are formed in the centerbody 310communicating with the process surface 312. A plurality of outletorifices 318 are formed in the centerbody 310, separate from the inletorifices 316, and also communicating with the process surface 312. Thecenterbody 310 includes an integral inlet fitting 324 defining an inletport 330 of the valve 300, and an integral outlet fitting 326 definingan outlet port 332 of the valve 300. An inlet manifold 327 is formedintegrally with the centerbody 310 and forms a fluid connection betweenthe inlet orifices 316 and the inlet fitting 324. An outlet manifold 329is formed integrally within the centerbody 310 and forms a fluidconnection between the outlet orifices 318 and the outlet fitting 326. Aportion of the outlet manifold 329 is open to the back surface 314.

The inlet and outlet fittings 324 and 326 may be functionally and/orstructurally integral to the centerbody 310. In one example, the fitting324, 326 may be formed as a physically unitary or integral part of thecenterbody 310, for example by molding, additive manufacturing, ormachining.

In another example, inlet and outlet fittings 324, 326 may bemanufactured separately and then fit into the centerbody 310. Examplesof suitable materials include metal alloys such as stainless steel, orthermoplastic materials. The fittings 324, 326 may be press fit into thecenterbody 310, the interference providing a secure joint. In oneexemplary combination, stainless steel barbs would be press fit into athermoplastic centerbody 310 having a Shore D hardness greater than 55.For the most secure press fit, the Shore D hardness of the centerbody310 may be greater than 70. Alternatively, the fittings 324, 326 couldbe bonded to the centerbody 310 using a process such as spin welding orultrasonic welding (if both the centerbody 310 and the fittings 324, 326are polymer).

The centerbody 310 (containing the orifices) may be manufactured usingvarious methods such as machining from a block of precursor material,additive manufacturing processes (e.g., “3-D printing”), or molding froma polymer suitable for the application requirements. Examples ofsuitable materials are the same as described above for the centerbody310.

A flexible control diaphragm or membrane 320, which may be substantiallyidentical to the control diaphragm 120 described above, is provided. Thecontrol diaphragm 320 includes opposed sides referred to as referenceand process sides and is disposed adjacent the process surface 312 withthe process side facing the process surface 312. The perimeter of thecontrol diaphragm 320 is sealed to the centerbody 110. The controldiaphragm 320 is continuous and is free from holes or other openingstherein, to form a fluid-tight boundary.

In the illustrated example, the outlet manifold 329 must be sealed offat the back surface 314 in order to define the appropriate fluidflowpath. Accordingly, a backside diaphragm or membrane 322 is disposedadjacent the back surface 314. The backside diaphragm 322 could be madefrom any of the materials listed for the control diaphragm 320. Theperimeter of the backside diaphragm 322 is sealed to the centerbody 310.

The control diaphragm 320 and/or backside diaphragm 322 may be containedby any support structure that is strong enough to provide physicalsupport for the control diaphragm 320. The configuration and material ofthe support structure may be similar to that of the support structuredescribed above for valve 100, including, optionally a gasket (notshown) to enhance the seal around the periphery of one or both of thediaphragms 320, 322.

In the illustrated example, the enclosure assembly 304 includes a topcap 306, a bottom support 308, and a retainer ring 309. The top 306 hasa disk-like shape with an internal reference cavity 336 and an integralreference port 338 connected in fluid communication with the referencecavity 336.

The bottom support 308 serves as a support structure for the backsidediaphragm 322. The bottom support 308 has a disk-like shape withclearance slots 342 for the inlet and outlet fittings 324, 326 describedabove. It also includes threads 344 around its upper periphery.

Means are provided for joining the components of the enclosure assembly304 and to hold pressure forces. In the illustrated embodiment, bestseen in FIGS. 13 and 20, ring-shaped retainer 346 incorporates threads348 which engages the threads 344 of the bottom support 308 to connectthe top cap 306 and bottom support 308 with the centerbody 310 clampedtherebetween.

FIG. 21 illustrates another alternative embodiment of a valve 400. Thevalve 400 is similar in construction to valve 100 described above andincludes a centerbody assembly 402 and an enclosure 404 including a topcap (or reference cap) 406.

The centerbody assembly 402 includes a centerbody 410 having a firstside defining a process surface 412, and an opposed second side defininga back surface 414. Both of the surfaces 412, 414 are generally planarin the illustrated example, but different geometries may be used, forexample, the surfaces 412, 414 may include various recesses orprotrusions.

At least one inlet orifice 416 passes through the centerbody 410 fromthe process surface 412 to the back surface 414. The function of theinlet orifice (or orifices) 416 is to bring the process fluid into thevalve 400. At least one outlet orifice 418 passes through the centerbody410 from the process surface 412 to the back surface 414.

The centerbody 410 (containing the orifices) may be manufactured usingvarious methods such as machining from a block of precursor material,additive manufacturing processes (e.g., “3-D printing”), or molding froma polymer suitable for the application requirements. For bestperformance in a single-use application where sterility is important, apolymer with USP class VI certification may be used. Nonlimitingexamples of such materials include polyolefin (e.g., polyethylene, LDPE,HDPE, UHMWPE), PEEK, acetal polymer (e.g. DELRIN), PTFE, and PFA.

A flexible control diaphragm or membrane 420 is disposed adjacent theprocess surface 412. For best performance in a single-use applicationwhere sterility is important, the control diaphragm 420 may be made froma material with USP class VI certification. Nonlimiting examples of suchmaterials include TPU, TPE, polyolefin (LDPE, HDPE, UHMWPE, PP, etc.),PEEK, PTFE, PFA, FEP, a sulfone polymer such as RADEL, silicone, orother similar thermoplastic elastomer such as SANTOPRENE.

The control diaphragm 420 has opposed sides, referred to as referenceand process sides, with the process side facing the process surface 412.The perimeter of the control diaphragm 420 is sealed to the centerbody410, for example by welding or adhesive, to maintain sterility and alsoto serve as a pressure boundary in use. The control diaphragm 420 iscontinuous and is free from holes or other openings therein, to form afluid-tight boundary.

In the illustrated example, the inlet orifices 416 and outlet orifices418 are formed as through-holes, which must be sealed off at the backsurface 414 in order to define the appropriate fluid flowpath.Accordingly, a backside diaphragm or membrane 422 is disposed adjacentthe back surface 414. The backside diaphragm 422 could be made from anyof the materials listed for the control diaphragm 420.

The perimeter of the backside diaphragm 422 is sealed to the centerbody410, for example by welding or adhesive, to maintain sterility up to thepoint of final use and also to serve as a pressure boundary in use.Additional bond lines may be provided to separate the inlet orifices 416from the outlet orifices 418 on the back surface 414. The backsidediaphragm 422 includes an inlet opening 417 and an outlet opening 419formed therein.

In the illustrated example, separate inlet and outlet fittings 424, 426respectively, are provided. Each of these has a flange 428 which issecured to the backside diaphragm 422, for example by welding oradhesive, to serve as inlet and outlet ports 430, 432 respectively, ofthe valve 400. A fluid passage 434 of the inlet fitting 424 communicateswith the inlet opening 417 of the backside diaphragm 422, and a fluidpassage 437 of the outlet fitting 426 communicates with the outletopening 419 of the backside diaphragm 422. For best performance in asingle-use application where sterility is important, the inlet andoutlet fittings 424, 426 may be made of a USP class VI thermoplastic.Examples of such materials are described above.

In the illustrated example, the enclosure assembly 404 includes top cap406 which serves to enclose the control diaphragm 420. The top cap 406has a disk-like shape and may be formed from the same material as thecontrol diaphragm 420. It includes an integral reference port 438connected in fluid communication with the space between itself and thecontrol diaphragm 420, referred to herein as a reference cavity 436. Theperiphery of the top cap 406 is secured to the control diaphragm 420,the centerbody 410, or both, through means such as welding or adhesive.

In this embodiment, no rigid structures are provided on the outside ofthe diaphragms 420 and 422, making it especially economical andconvenient as it minimizes the amount of material and can be completelydiscarded after a predetermined number of uses. The lack of rigidstructures makes this embodiment generally more suitable for relativelylow maximum pressures, for example, less than 70 kPa (10), or less than35 kPa (5 PSI).

The valves described above has numerous advantages over prior artvalves. They are of simple construction and are sufficiently economicalthat they can be considered single-use and/or disposal these valves havethe capability to minimize disposal waste of valve materials. Theypresent few wetted materials in their construction. They may be madefrom materials that can be sterilized and are compatible withbiochemical processes such as USP class VI certified and BPA-freepolymers

The foregoing has described an apparatus for single-use valves. All ofthe features disclosed in this specification (including any accompanyingclaims, abstract and drawings), and/or all of the steps of any method orprocess so disclosed, may be combined in any combination, exceptcombinations where at least some of such features and/or steps aremutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings) may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The invention is not restricted to the details of the foregoingembodiment(s). The invention extends any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

What is claimed is:
 1. A centerbody assembly for a valve, comprising: acenterbody having a first side which defines a process surface and anopposed second side defining a back surface, at least one inlet orificedisposed in the centerbody and adapted to be disposed in fluidcommunication with a fluid at a process pressure, and at least oneoutlet orifice disposed in the centerbody separate from the at least oneinlet orifice; an inlet port disposed in fluid communication with the atleast one inlet orifice; an outlet port disposed in fluid communicationwith the at least one outlet orifice; and a flexible control diaphragmhaving opposed reference and process sides, wherein the controldiaphragm is positioned with the process side facing the processsurface, and a perimeter of the control diaphragm is sealed to thecenterbody.
 2. A valve, comprising: a centerbody assembly including: acenterbody having a first side which defines a process surface and anopposed second side defining a back surface, at least one inlet orificedisposed in the centerbody and adapted to be disposed in fluidcommunication with a fluid at a process pressure, and at least oneoutlet orifice disposed in the centerbody separate from the at least oneinlet orifice; a flexible control diaphragm having opposed reference andprocess sides, wherein the control diaphragm is positioned with theprocess side facing the process surface, and a perimeter of the controldiaphragm is sealed to the centerbody; an inlet port disposed in fluidcommunication with the at least one inlet orifice; and an outlet portdisposed in fluid communication with the at least one outlet orifice;and an enclosure assembly including a top cap adapted to be disposed influid communication with a fluid at a predetermined reference pressure,wherein the control diaphragm is positioned between the centerbody andthe top cap, and arranged such that, when the reference pressure ishigher than the process pressure the diaphragm is engaged with theoutlet orifices, and when the process pressure is higher than thereference pressure, the diaphragm is not engaged with at least one ofthe outlet orifices.